• She suffers from rare hydranencephaly, missing large parts of the brain
• Doctors predicted her life would not exceed four years

An American woman born without large parts of her brain celebrated her 20th birthday, despite doctors’ predictions that she would not live past four years.

Alex Simpson was born in November 2005, and her parents were told she was a healthy baby at birth. However, two months later during a check-up, doctors discovered she had hydranencephaly, a rare disorder affecting brain development that often leads to early death.

Despite missing the parts responsible for sight and hearing, the family says Alex can sense their presence and shows more awareness than people might think.

Her father, Shawn, said: "It means her brain is not there, and she only has a very tiny part of the cerebellum at the back of her brain, and that’s all there is."

He added that the reason for her survival might be “love.”

Her 14-year-old brother confirmed Alex’s ability to sense emotions and situations around her, even in complete silence: "She can tell if someone is in pain or feeling upset… it’s amazing."

The family calls Alex a “miracle,” and her brother says he is proud of her and proud to talk about her.

Her father said: "We were scared 20 years ago, but faith is what kept us going."

Studies indicate this condition is extremely rare, occurring in about one in every 5,000 to 10,000 births.

The exact cause is still unknown, but it may be linked to genetics or exposure to certain toxins during pregnancy.

Symptoms of the condition include failure to grow normally, abnormal muscle tone, larger-than-normal head size, vision and hearing problems, stiff limbs, and breathing difficulties.